Synthesis and characterization of monodisperse hematite nanoparticles modified by surfactants via hydrothermal approach

Monodisperse rhombohedral alpha-Fe2O3 nanoparticles modified by four different surfactants, sodium dodecylsulfonate (SDS), sodium dodecylebenzene sulphonate (DBS), cetyltrimethyl ammonium bromide (CTAB) and hexadecyipyridinium chloride (HPC), have been synthesized via hydrothermal method, using FeC2O4 and NaOH as starting precursors. Meanwhile, monodisperse rodlike alpha-Fe2O3 nanoparticles without surfactant are also prepared under the same conditions for comparison. The products were characterized by means of Fourier transform infrared spectroscopy (FT-IR), X-ray diffraction (XRD), transmission electron micrograph (TEM) and magnetization measurements. The products with and without surfactant all exhibit weak ferromagnetic properties at room temperature, except somewhat variation in coercivity values. The experimental results suggest that the surfactants can significantly influence the size and shape of the particles, but cannot affect their magnetic nature. (C) 2004 Elsevier B.V. All rights reserved.